Build Your Own Combat Robot

208 Build Your Own Combat Robot
Wedge Bots
Wedge Design
The wedge was first used in the robot Slow Moe (Robot Wars, 1994. Examples of
robots using a wedge include La Machine, Punjar, Bad Attitude, and Subject to
Change Without Reason.
The wedge weapon features a thin, wide, ground-scraping scoop on the front,
backed up by a strong frame and powerful drive system.
Like the ram, the wedge’s main weapon is its drive power and the ability to hit
and push its opponent. Rather than simply impact, the wedge uses an inclined
scoop front to lift the opponent on impact, breaking its contact with the ground
and depriving it of traction. A well-made wedge bot can keep the opponent from
escaping while being pushed by maintaining enough forward power to keep the
scoop front under the opponent while shoving it across the arena.
The wedge design comes down to two things: enough power in the drive train
and proper engineering of the scoop front. Power requirements of a wedge are
similar to those of the ram—at least 1 HP per 50 pounds of robot weight (more, if
possible), a drive gearing giving a top speed of 15 to 20 MPH, and pushing power
of twice the robot’s weight or more. Wedges should be two or four wheeled: a
two-wheeled design will give faster turning rates; make the wedge more nimble;
and allow a wide, short shape with maximum impact surface on the scoop. A
four-wheeled wedge will be more stable and drive in accurate straight lines.
Six-wheeled robots tend to be significantly longer than they are wide; this is not
desirable for a wedge, which is better off wide and short. Figure 10-2 shows a classic
wedge design.
The lower front edge of the wedge is the most critical part of the robot. This
part should be thin and sharp to be able to get under other low-built opponents.
Also, it should be as durable as possible because it will bear the brunt of
full-speed impacts with the opponent; the arena walls; and any obstacles,
arena hazards, or irregular spots in the floor that the wedge runs into. If possible,
the lower edge of the front should be an integral part of the frame, rather
than just an angled sheet of metal attached to the frame and not supported at
the lower edge. Many wedges have been disabled when their own wedge front
was bent downward, propping the front of the wedge off the ground and
breaking the wheel’s contact with the ground.
The surface of the wedge must also be strong enough to take the weight of the
target robot held on top of it. If insufficiently supported, the wedge’s front can be
driven down into the ground, stopping it and preventing it from pushing the opponent
further. Flexible materials should not be used for the leading edge of the
wedge, as these will drag badly on the ground once an opponent is on top. If a
hinged flap is used for the wedge, it must be rigid and supported from underneath
with structural standoffs that limit its movement so that it won’t drag on the ground.